Although it looks hard to tell from the scan, I'm thinking your "deformity" is actually a blob of glue. Transparent glue can often look like blobs of metal, as
some of our members have discovered. I'm guessing someone made a display featuring this Australian dollar, with the more interesting kangaroo reverse side facing out.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis